(1) if we change blockMeshDict to: (see the end of the message)
(2) run blockMesh and then checkMesh
(3) we get from checkMesh:
Mesh non-orthogonality Max: 45 average: 36.4151
(4) I expected :
Mesh non-orthogonality Max: 45 average: (2/3)*45=30.
since 1/3 of the mesh hax non-othogonality=0 (faces normal to z directions).